The potential of high-resolution BAC-FISH in banana breeding     

Guy De Capdeville  Manoel Teixeira Souza Júnior  Dóra Szinay  Leandro Eugênio Cardamone Diniz  Erik Wijnker  Rony Swennen  Gerrit Haatje Jan Kema  Hans De Jong 《Euphytica》2009,166(3):431-443

The genetic complexity in the genus Musa has been subject of study in many breeding programs worldwide. Parthenocarpy, female sterility, polyploidy in different cultivars and limited amount of genetic and genomic information make the production of new banana cultivars difficult and time consuming. In addition, it is known that part of the cultivars and related wild species in the genus contain numerous chromosomal rearrangements. In order to produce new cultivars more effectively breeders must better understand the genetic differences of the potential crossing parents for introgression hybridization, but extensive genetic information is lacking. As an alternative to achieve information on genetic collinearity we make use of modern chromosome map technology known as high-resolution fluorescent in situ hybridization (FISH). This article presents the technical aspects and applications of such a technology in Musa species. The technique deals with BAC clone positioning on pachytene chromosomes of Calcutta 4 (Musa acuminata ssp. burmanicoides, A genome group, section Eumusa) and M. velutina (section Rodochlamys). Pollen mother cells digestion with pectolytic enzymes and maceration with acetic acid were optimized for making cell spread preparations appropriate for FISH. As an example of this approach we chose BAC clones that contain markers to known resistance genes and hybridize them for establishing their relative positions on the two species. Technical challenges for adapting existing protocols to the banana cells are presented. We also discuss how this technique can be instrumental for validating collinearity between potential crossing parents and how the method can be helpful in future mapping initiatives, and how this method allows identification of chromosomal rearrangements between related Musa species and cultivars.  相似文献   

Morphological and biochemical responses of Balanites aegyptiaca to drought stress and recovery are provenance‐dependent     

Galal Khamis  AbdElgawad Hamada  Frank Schaarschmidt  Gerrit T. S. Beemster  Han Asard  Jutta Papenbrock 《Journal of Agronomy and Crop Science》2019,205(5):490-507

Balanites aegyptiaca is a drought‐tolerant tree naturally distributed in Africa and has a high potential for biofuel production and livelihood. To understand the plant tolerance to drought stress, B. aegyptiaca plants collected from five provenances were subjected for 4 weeks to drought stress through different regimes of soil volumetric water content (VWC, i.e. 25% control, 15% as moderate and 5% as a severe drought stress) followed by 2‐week recovery. Morpho‐physiological responses as well as the changes in antioxidant defences under water stress and recovery were investigated. Drought stress significantly reduced plant biomass‐related parameters, stomatal conductance, quantum efficiency and increased leaf temperature. Each provenance showed specific patterns of stress response reactions that were detected in a cluster analysis. The large leaf area and a high level of lipid peroxidation in Cairo provenance increased its sensitivity to severe drought. For provenances El‐Kharga and Yemen, the highest tocopherol contents and the highest catalytic activities of ascorbate peroxidase (SOD), catalase (CAT), glutathione reductase (GR) and dehydroascorbate reductase (DHAR) were recorded. These traits contributed to the high drought tolerance of these two provenances in comparison with the other provenances. All plants recovered from stress and showed specifically increased activity of glutathione‐S‐transferase (GST) as a repair mechanism. Results showed that the drought tolerance level in B. aegyptiaca is provenance‐dependent.  相似文献   

Application of the CSM-CERES-Maize model for planting date evaluation and yield forecasting for maize grown off-season in a subtropical environment   总被引：1，自引：0，他引：1  

Cecilia Manuela Tojo Soler  Paulo Csar Sentelhas  Gerrit Hoogenboom 《European Journal of Agronomy》2007,27(2-4):165-177

In recent years, maize has become one of the main alternative crops for the Autumn–Winter growing season (off-season) in several regions of Brazil. Water deficits, sub-optimum temperatures and low solar radiation levels are some of the more common problems that are experienced during this growing season. However, the impact of variable weather conditions on crop production can be analyzed with crop simulation models. The objectives of this study were to evaluate the Cropping System Model (CSM)-CERES-Maize for its ability to simulate growth, development, grain yield for four different maturity maize hybrids grown off-season in a subtropical region of Brazil, to study the impact of different planting dates on maize performance under rainfed and irrigated conditions, and for yield forecasting for the most common off-season production system. The CSM-CERES-Maize model was evaluated with experimental data collected during three field experiments conducted in Piracicaba, SP, Brazil. The experiments were completely randomized with three replications for the 2001 experiment and four replications for the 2002 experiments. For the yield forecasting application, daily weather data for 2002 were used until the forecast date, complemented with 25 years of historical daily weather data for the remainder of the growing season. Six planting dates were simulated, starting on February 1 and repeated every 15 days until April 15. The evaluation of the CSM-CERES-Maize showed that the model was able to simulate phenology and grain yield for the four hybrids accurately, with normalized RMSE (expressed in percentage) less than 15%. The planting date analysis showed that a delayed planting date from February 1 to April 15 caused a decrease in average yield of 55% for the rainfed and 21% for the irrigated conditions for all hybrids. The yield forecasting analysis demonstrated that an accurate yield forecast could be provided at approximately 45 days prior to the harvest date for all four maize hybrids. These results are promising for farmers and decision makers, as they could have access to accurate yield forecasts prior to final harvest. However, to be able to make practical decisions for stock management of maize grains, it is necessary to develop this methodology for different locations. Future model evaluations might also be needed due to the release of new cultivars by breeders.  相似文献   

The impact of uptake, translocation and metabolism on the differential selectivity between blackgrass and wheat for the herbicide pyroxsulam     

DeBoer GJ  Thornburgh S  Gilbert J  Gast RE 《Pest management science》2011,67(3):279-286

BACKGROUND: Wheat shows selectivity to pyroxsulam, a new broad‐spectrum herbicide with high activity on blackgrass. Studies were performed to establish whether uptake, translocation or metabolism were responsible for the differential activity in wheat compared with blackgrass. In addition, the effect of the safener cloquintocet‐mexyl on metabolism was evaluated in wheat and blackgrass shoots. RESULTS: Root uptake of pyroxsulam in blackgrass was significantly higher than in wheat, suggesting a possible activity enhancement in blackgrass owing to root uptake. Translocation to foliage from root uptake as well as translocation out of treated foliage following foliar applications was low in wheat compared with blackgrass, likely owing to the rapid metabolism of pyroxsulam in wheat. Wheat metabolized pyroxsulam significantly faster than blackgrass to the less active O‐dealkylation product. Wheat shoots metabolized pyroxsulam faster when the safener cloquintocet‐mexyl was present, but cloquintocet‐mexyl did not increase the rate of metabolism in blackgrass. CONCLUSIONS: The selectivity of pyroxsulam to wheat relative to blackgrass was connected primarily with differences in the rate of metabolism and generation of an inactive metabolite. Metabolism in wheat restricted subsequent movement of radioactivity out of the treated leaf. The rapid metabolism in wheat was increased by the addition of cloquintocet‐mexyl. Copyright © 2010 Society of Chemical Industry  相似文献   

Soy isoflavones and other isoflavonoids activate the human bitter taste receptors hTAS2R14 and hTAS2R39     

Roland WS  Vincken JP  Gouka RJ  van Buren L  Gruppen H  Smit G 《Journal of agricultural and food chemistry》2011,59(21):11764-11771

The aim of this study was to identify the bitter receptor(s) that recognize the bitter taste of the soy isoflavone genistein. Screening of all 25 human bitter receptors revealed genistein as agonist of hTAS2R14 and hTAS2R39. Genistein displayed threshold values of 4 and 8 μM on hTAS2R14 and hTAS2R39 and EC(50) values of 29 and 49 μM, respectively. In addition, the behavior of structurally similar isoflavonoids was investigated. Although the two receptors are not closely related, the results for hTAS2R14 and hTAS2R39 were similar toward most isoflavonoid aglycones. By trend, threshold values were slightly lower on hTAS2R14. Glucosylation of isoflavones seemed to inhibit activation of hTAS2R14, whereas four of five glucosylated isoflavones were agonists of hTAS2R39, namely, glycitin, genistin, acetylgenistin, and malonylgenistin. A total of three hydroxyl substitutions of the A- and B-rings of the isoflavonoids seemed to be more favorable for receptor activation than fewer hydroxyl groups. The concentration of the trihydroxylated genistein in several soy foods exceeds the determined bitter receptor threshold values, whereas those of other soy isoflavones are around or below their respective threshold value. Despite its low concentration, genistein might be one of the main contributors to the bitterness of soy products. Furthermore, the bioactive isoflavonoids equol and coumestrol activated both receptors, indicating that their sensory impact should be considered when used as food ingredients.  相似文献   

Theileria sergenti     

Uilenberg G 《Veterinary parasitology》2011,175(3-4):386

  相似文献   

Discovery and characterization of sulfoxaflor, a novel insecticide targeting sap-feeding pests   总被引：5，自引：0，他引：5  

Zhu Y  Loso MR  Watson GB  Sparks TC  Rogers RB  Huang JX  Gerwick BC  Babcock JM  Kelley D  Hegde VB  Nugent BM  Renga JM  Denholm I  Gorman K  DeBoer GJ  Hasler J  Meade T  Thomas JD 《Journal of agricultural and food chemistry》2011,59(7):2950-2957

The discovery of sulfoxaflor [N-[methyloxido[1-[6-(trifluoromethyl)-3-pyridinyl]ethyl]-λ(4)-sulfanylidene] cyanamide] resulted from an investigation of the sulfoximine functional group as a novel bioactive scaffold for insecticidal activity and a subsequent extensive structure-activity relationship study. Sulfoxaflor, the first product from this new class (the sulfoximines) of insect control agents, exhibits broad-spectrum efficacy against many sap-feeding insect pests, including aphids, whiteflies, hoppers, and Lygus, with levels of activity that are comparable to those of other classes of insecticides targeting sap-feeding insects, including the neonicotinoids. However, no cross-resistance has been observed between sulfoxaflor and neonicotinoids such as imidacloprid, apparently the result of differences in susceptibility to oxidative metabolism. Available data are consistent with sulfoxaflor acting via the insect nicotinic receptor in a complex manner. These observations reflect the unique structure of the sulfoximines compared with neonicotinoids.  相似文献   

DSSAT作物模型的统计和图形校验方法   总被引：2，自引：0，他引：2  

杨靖民  杨靖一 《植物营养与肥料学报》2012,18(5):1065-1074

本文以玉米, 大豆, 马铃薯和冬小麦试验为例, 详细讨论了DSSAT模型的统计校验和图形校验方法及其支持软件EasyGrapher的应用。结果指出: R2 不是理想的模型校验统计,因为它是测量线性回归y = + x + 的拟合度, 其随机误差建立在正态性、 相互独立和方差同质的假设之上。模型校验主要是检验残差di = yi-xi（y 为测量值, x为模拟值）,不是估计回归系数、 。RMSE、 E、 EF 和 d 都是比较好的校验模型残差的统计量, 它们不需要遵循回归模型的基本假设, 统计量的物理意义明确, 大样本容量下统计校验更为可靠。图形校验是模型校验必不可少的辅助工具,当有测量数据时,时间序列和残差校验图形是两种最基本的图形校验方法; 没有测量数据, 模拟图形仍然能够检验模型输出之间或与时间的动态关系, 辨析模拟误差或者错误。应用EasyGrapher 软件可以快速进行DSSAT模型的图形校验和统计校验。  相似文献   

Glycosylation of Conotoxins     

Gerrit J. Gerwig  Henry G. Hocking  Reto St?cklin  Johannis P. Kamerling  Rolf Boelens 《Marine drugs》2013,11(3):623-642

Conotoxins are small peptides present in the venom of cone snails. The snail uses this venom to paralyze and capture prey. The constituent conopeptides display a high level of chemical diversity and are of particular interest for scientists as tools employed in neurological studies and for drug development, because they target with exquisite specificity membrane receptors, transporters, and various ion channels in the nervous system. However, these peptides are known to contain a high frequency and variability of post-translational modifications—including sometimes O-glycosylation—which are of importance for biological activity. The potential application of specific conotoxins as neuropharmalogical agents and chemical probes requires a full characterization of the relevant peptides, including the structure of the carbohydrate part. In this review, the currently existing knowledge of O-glycosylation of conotoxins is described.  相似文献   

Determining FAO-56 crop coefficients for peanut under different water stress levels     

Ayman A. Suleiman  Cecilia M. Tojo Soler  Gerrit Hoogenboom 《Irrigation Science》2013,31(2):169-178

Accurate estimates of peanut (Arachis hypogaea L.) water requirements are needed for water conservation. The objective of this study was to evaluate the FAO-56 crop coefficients for peanut grown under various levels of water stress in a humid climate. Two experiments were conducted in three automated rainout shelters located at the University of Georgia Griffin Campus in Griffin, Georgia, USA in 2006 and 2007. Irrigation was applied when the modeled soil water content in the effective root zone dropped below a specific threshold of the available water content (AWC). The irrigation treatments corresponded to irrigation thresholds (IT) of 40, 60 and 90% of AWC. The soil water balance was used to compute observed evapotranspiration (ET _cm) from measured soil water content at six different soil depths. The length of the four developmental stages was different than the values listed in FAO-56. The 2-year average absolute relative error of K _cini was 8, 19 and 6% for 40, 60 and 90% IT, respectively. For the 90% IT, the FAO-56 K _cmid and K _cend were almost identical to the 2-year averages of the observed K _cmid and K _cend, respectively. The findings of this study confirmed that the FAO-56 procedure was reasonably accurate for estimating peanut ET under water stress in a humid climate.  相似文献